Why is everyone saying Quake GL? Quake was and still is and amazing game, i remember trying the GL patch and it seemed to make it worse. Well, not worse, it looked more smooth and played much better but Quake to me was a dark and old type of game. Meant to be played in software mode, either 640x480 or 320x240. No need for open GL and 1024x768. Unreal was for that
Edit - Just like Doom, Im playing through Zdoom i think it is now (or Jdoom) in 320x240 mode, software everything with original sounds and non of the stupid new shadow, lighting and smoothing effects.